[Buildroot] [PATCH v2] modem-manager: select libgudev, if systemd is enabled

[yegorslists at googlemail.com]

From: Yegor Yefremov <yegorslists at googlemail.com>

When eudev is used as the udev provider, libgudev is automatically
provided as it is part of eudev. However, when systemd is used as
the udev provider, libgudev is not provided, and needs to be built
separately. This is why we select the libgudev package only if
systemd is used.

Fixes: http://autobuild.buildroot.net/results/d59/d597a81271a082c8252e2333906815c437b6576d/

Signed-off-by: Yegor Yefremov <yegorslists at googlemail.com>
---
Changes:
	v2: change patch name (Vicente Olivert Riera)
	    add fix description (Vicente Olivert Riera)
	    add explanations to Config.in and *.mk files (Vicente Olivert Riera)

 package/modem-manager/Config.in        | 6 ++++++
 package/modem-manager/modem-manager.mk | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/package/modem-manager/Config.in b/package/modem-manager/Config.in
index 59b8d88..80688f2 100644
--- a/package/modem-manager/Config.in
+++ b/package/modem-manager/Config.in
@@ -6,6 +6,12 @@ config BR2_PACKAGE_MODEM_MANAGER
 	depends on BR2_TOOLCHAIN_HAS_THREADS # dbus, libglib2
 	depends on BR2_USE_MMU # dbus
 	select BR2_PACKAGE_DBUS_GLIB
+	# When eudev is used as the udev provider, libgudev is automatically
+	# provided as it is part of eudev. However, when systemd is used as
+	# the udev provider, libgudev is not provided, and needs to be built
+	# separately. This is why we select the libgudev package only if
+	# systemd is used.
+	select BR2_PACKAGE_LIBGUDEV if BR2_INIT_SYSTEMD
 	help
 	  ModemManager is a DBus-activated daemon which controls mobile
 	  broadband (2G/3G/4G) devices and connections.
diff --git a/package/modem-manager/modem-manager.mk b/package/modem-manager/modem-manager.mk
index 0e6b36a..9f311fe 100644
--- a/package/modem-manager/modem-manager.mk
+++ b/package/modem-manager/modem-manager.mk
@@ -12,6 +12,15 @@ MODEM_MANAGER_LICENSE_FILES = COPYING
 MODEM_MANAGER_DEPENDENCIES = host-pkgconf udev dbus-glib host-intltool
 MODEM_MANAGER_INSTALL_STAGING = YES
 
+# When eudev is used as the udev provider, libgudev is automatically
+# provided as it is part of eudev. However, when systemd is used as the
+# udev provider, libgudev is not provided, and needs to be built
+# separately. This is why we select the libgudev package only if systemd
+# is used.
+ifeq ($(BR2_INIT_SYSTEMD),y)
+MODEM_MANAGER_DEPENDENCIES += libgudev
+endif
+
 ifeq ($(BR2_PACKAGE_MODEM_MANAGER_LIBQMI),y)
 MODEM_MANAGER_DEPENDENCIES += libqmi
 MODEM_MANAGER_CONF_OPTS += --with-qmi
-- 
2.1.4